scholarly journals Comparative analysis of the anatomy of two populations of red-root amaranth (Amaranthus retroflexus L.)

2009 ◽  
Vol 24 (2) ◽  
pp. 103-112 ◽  
Author(s):  
Sava Vrbnicanin ◽  
Lidija Stefanovic ◽  
Dragana Bozic ◽  
Marija Saric ◽  
Radenko Radosevic
Keyword(s):  
Arable Land ◽  
Amaranthus Retroflexus ◽  
Central Cylinder ◽  
Weed Species ◽  
Stem Anatomy ◽  
Typical Structure ◽  
Resistance To Herbicides ◽  
Two Populations ◽  
Very High ◽  
Herbaceous Dicots

The anatomy of stems and leaves of two populations of the weed species Amaranthus retroflexus L. (red-root amaranth) (pop. AMARE1 having green stems covered in sparse hairs and pop. AMARE2 with green but notably dense stem hairs) was analysed in order better to understand the uptake and translocation of herbicides that could be indicative of the species' evolving resistance to herbicides. Samples of the two populations (AMARE1 and AMARE2) were collected from arable land of the Institute of Maize Research at Zemun Polje in 2006. Sampling was performed at the stage of full vegetative growth of plants. Permanent microscoping preparations were made to measure and analyze elements of the anatomy of stems (stem epidermis, cortex, collenchyma, central cylinder and diameter) and leaves (leaf epidermis upper surface and underside, mesophyll, leaf thickness and bundle sheath thickness). Both analysed populations of A. retroflexus, morphologically characterized by different density of stem hairiness, were found to have a typical structure of herbaceous dicots. The stem had three distinctive zones: epidermis, cortex and central cylinder. Amaranth leaves have dorsoventral structure, i.e. their upper surface and underside can be differentiated. The results indicated high and very high significance of differences found in stem anatomy between the two analysed populations, while leaf anatomy was not found to display significant differences other than in mesophyll thickness.

A Review of Herbicide Resistance in Iran

Weed Science ◽  
2016 ◽  
Vol 64 (4) ◽  
pp. 551-561 ◽  
Author(s):  
Javid Gherekhloo ◽  
Mostafa Oveisi ◽  
Eskandar Zand ◽  
Rafael De Prado
Keyword(s):  
Herbicide Resistance ◽  
Crop Production ◽  
Arable Land ◽  
Wheat Crop ◽  
Wild Oat ◽  
Weed Species ◽  
Wild Mustard ◽  
Development Of Resistance ◽  
Resistance To Herbicides ◽  
Continuous Use

Continuous use of herbicides has triggered a phenomenon called herbicide resistance. Nowadays, herbicide resistance is a worldwide problem that threatens sustainable agriculture. A study of over a decade on herbicides in Iran has revealed that herbicide resistance has been occurring since 2004 in some weed species. Almost all the results of these studies have been published in national scientific journals and in conference proceedings on the subject. In the current review, studies on herbicide resistance in Iran were included to provide a perspective of developing weed resistance to herbicides for international scientists. More than 70% of arable land in Iran is given over to cultivation of wheat, barley, and rice; wheat alone covers nearly 52%. Within the past 40 years, 108 herbicides from different groups of modes of action have been registered in Iran, of which 28 are for the selective control of weeds in wheat and barley. Major resistance to ACCase-inhibiting herbicides has been shown in some weed species, such as winter wild oat, wild oat, littleseed canarygrass, hood canarygrass, and rigid ryegrass. With respect to the broad area of wheat crop production and continuous use of herbicides with the sole mechanism of action of ACCase inhibition, the provinces of West Azerbaijan, Tehran, Khorasan, Isfahan, Markazi, and Semnan are at risk of resistance development. In addition, because of continuous long-term use of tribenuron-methyl, resistance in broadleaf species is also being developed. Evidence has recently shown resistance of turnipweed and wild mustard populations to this herbicide. Stable monitoring of fields in doubtful areas and providing good education and training for technicians and farmers to practice integrated methods would help to prevent or delay the development of resistance to herbicides.

scholarly journals Weed resistance to herbicides

2020 ◽  
Vol 29 (2) ◽  
pp. 79-96
Author(s):  
Sava Vrbničanin
Keyword(s):  
Herbicide Resistance ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Target Site ◽  
Weed Species ◽  
Ps Ii ◽  
Target Site Resistance ◽  
Resistance To Herbicides ◽  
Als Inhibitors ◽  
Weed Resistance

Weed resistance to herbicides represents the acquired resistance of individuals to complete the life cycle and leave offspring in the conditions of extended exposure to the same herbicide, i.e. herbicides of the same mechanism of action to which they were sensitive at the beginning of the application. Based on the herbicide resistance mechanisms, all processes can be grouped as follows: target-site resistance, non-target-site resistance, cross-resistance and multiple-resistance. Currently, herbicide resistance has been reported in 514 cases (species x site of action) worldwide, in 262 weed species (152 dicotyledons, 110 monocotyledons). Many of those biotypes are resistant to als inhibitors, PS II inhibitors, EPSPS inhibitors and ACC-ase inhibitors. The higher degree of resistance to als inhibitors has been confirmed in the following weed species: Amaranthus retroflexus, Sorghum halepense, Ambrosia artemisiifolia and Helianthus annuus.

scholarly journals The problems of presence of weeds in the crops begin with seeds

2019 ◽  
pp. 26-28
Author(s):  
O. Ivashchenko ◽  
S. Remenyuk
Keyword(s):  
Chenopodium Album ◽  
Arable Land ◽  
Synthesis Method ◽  
Steppe Zone ◽  
Amaranthus Retroflexus ◽  
Forest Steppe ◽  
Weed Species ◽  
Climatic Zones ◽  
Analysis And Synthesis ◽  
Solanum Nigrum L

Goal. Determine the level of potential abrasion of arable land in the main soil-climatic zones of the country. Methods. Used methods of analysis and synthesis, method of comparison. Results. The total reserves of different types of weed seeds in the earth’s horizon 0—10 cm in the main soil-climatic zones of the country on average are: Polissya — 49 thousand pieces/m2; in the forest-steppe zone — 57 thousand pieces/m2; in the Steppe area on average — 57 thousand pieces/m2. Accordingly, during the warm period of the year, 1 m2 of arable land area is able to sprout and form stairs of weeds of various types of weeds on average: in the Polissya area — 1887 pieces; in the zone of forest-steppe — 4674 pieces; in the Steppe zone — 2242 pieces. Basically, these types of tetrophytes are annual weed species, for which the main way of reproduction and distribution is the fruits and seeds: millet cock Echinochloa crus-galli (L.) Pal. Beauv.; Loboda white Chenopodium album L., Common curd (curved) Amaranthus retroflexus L., Field mustard Sinapis arvensis L., Black passion black Solanum nigrum L. and others. Conclusions. Reducing the costs of systems for protecting crops from crops from weeds is possible, in the first place, with the reduction of the depot volume of their seeds in the arable layer of soil.

scholarly journals Effect of Clay, Soil Organic Matter, and Soil pH on Initial and Residual Weed Control with Flumioxazin

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1326
Author(s):  
Calvin F. Glaspie ◽  
Eric A. L. Jones ◽  
Donald Penner ◽  
John A. Pawlak ◽  
Wesley J. Everman
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Weed Control ◽  
Soil Ph ◽  
Organic Matter Content ◽  
Amaranthus Retroflexus ◽  
Matter Content ◽  
Weed Species ◽  
Soil Organic Matter Content ◽  
Field Soils

Greenhouse studies were conducted to evaluate the effects of soil organic matter content and soil pH on initial and residual weed control with flumioxazin by planting selected weed species in various lab-made and field soils. Initial control was determined by planting weed seeds into various lab-made and field soils treated with flumioxazin (71 g ha−1). Seeds of Echinochloa crus-galli (barnyard grass), Setaria faberi (giant foxtail), Amaranthus retroflexus (redroot pigweed), and Abutilon theophrasti (velvetleaf) were incorporated into the top 1.3 cm of each soil at a density of 100 seeds per pot, respectively. Emerged plants were counted and removed in both treated and non-treated pots two weeks after planting and each following week for six weeks. Flumioxazin control was evaluated by calculating percent emergence of weeds in treated soils compared to the emergence of weeds in non-treated soils. Clay content was not found to affect initial flumioxazin control of any tested weed species. Control of A. theophrasti, E. crus-galli, and S. faberi was reduced as soil organic matter content increased. The control of A. retroflexus was not affected by organic matter. Soil pH below 6 reduced flumioxazin control of A. theophrasti, and S. faberi but did not affect the control of A. retroflexus and E. crus-galli. Flumioxazin residual control was determined by planting selected weed species in various lab-made and field soils 0, 2, 4, 6, and 8 weeks after treatment. Eight weeks after treatment, flumioxazin gave 0% control of A. theophrasti and S. faberi in all soils tested. Control of A. retroflexus and Chenopodium album (common lambsquarters) was 100% for the duration of the experiment, except when soil organic matter content was greater than 3% or the soil pH 7. Eight weeks after treatment, 0% control was only observed for common A. retroflexus and C. album in organic soil (soil organic matter > 80%) or when soil pH was above 7. Control of A. theophrasti and S. faberi decreased as soil organic matter content and soil pH increased. Similar results were observed when comparing lab-made soils to field soils; however, differences in control were observed between lab-made organic matter soils and field organic matter soils. Results indicate that flumioxazin can provide control ranging from 75–100% for two to six weeks on common weed species.

scholarly journals Weed Interference Affects Dry Bean Yield and Growth

2012 ◽  
Vol 4 (3) ◽  
pp. 70-75 ◽  
Author(s):  
Hossein GHAMARI ◽  
Goudarz AHMADVAND
Keyword(s):  
Chenopodium Album ◽  
Growing Season ◽  
Amaranthus Retroflexus ◽  
Growth And Yield ◽  
Weed Competition ◽  
Weed Species ◽  
Dry Bean ◽  
Logistic Equations ◽  
Weed Interference ◽  
Minimum Number

Dry bean is one of the most important pulse crops in Iran. Field study was conducted in 2011 to evaluate effects of weed competition from a natural flora on growth and yield of dry bean (Phaseolus vulgaris L.). The treatments consisted of weed infestation and weed removal periods (10, 20, 30, 40 and 50 days) after crop emergence. Control plots kept weed-infested and weed-free throughout growing season. To assess the weed competition effect on crop characteristics, Richards, Gompertz and logistic equations were fitted to the data. The most abundant weed species were Chenopodium album and Amaranthus retroflexus. Increase in duration of weed interference decreased the stem height of dry bean. At the end of the growing season, dry bean was 20 cm taller in season-long weed-free treatment compared to the season-long weed-infested treatment. As the number of days of weed interference increased, a declining trend of LAI and number of pods was observed. The minimum number of pods was obtained in season-long weed-infested treatment (5.01 pods/plant). Weed interference during the whole growing season, caused a 60% reduction in yield. Considering 5% and 10% acceptable yield lost, the critical period of weed competition was determined from 20 to 68 and 23 to 55 days after planting (DAE), respectively.

scholarly journals Weed Species Diversity in the Czech Republic Under Different Farming and Site Conditions

2015 ◽  
Vol 63 (3) ◽  
pp. 741-749 ◽  
Author(s):  
Michaela Kolářová ◽  
Luděk Tyšer ◽  
Josef Soukup
Keyword(s):  
Czech Republic ◽  
Organic Farming ◽  
Chenopodium Album ◽  
Arable Land ◽  
Farming Systems ◽  
Weed Species ◽  
Organic Farms ◽  
Standard Size ◽  
The Czech Republic ◽  
Winter Cereals

The aim of this study was to explore the composition of weed vegetation on arable land in selected areas of the Czech Republic and to determine the level of γ-diversity. Our survey was conducted at 27 conventional and 35 organic farms from 2006–2008. In each sampled field, one phytocoenological relevé of a standard size of 100 m2 was recorded in the central part of the field. The species cover was estimated. The total γ-diversity was expressed as the total number of weed species recorded. γ-diversity of different farming systems, altitudes and crops was calculated. Subsequently, the species were divided on the basis of their perenniality. In total, 172 weed species were found – 123 and 162 in conventional and organic farming, respectively. The highest number of species was found in winter cereals and at medium altitudes. Chenopodium album was recorded as the species with the highest constancy in both types of farming. In total, 89 annuals, 17 biennials and 15 perennials were observed in conventional farming, and 109 annuals, 23 biennials, 28 perennials and 2 semiparasitic annuals were found in organic farming.

scholarly journals Assessment of weed establishment risk in a changing European climate

2012 ◽  
Vol 21 (4) ◽  
pp. 348-360 ◽  
Author(s):  
Terho Hyvönen ◽  
Miska Luoto ◽  
Pertti Uotila
Keyword(s):  
Explanatory Power ◽  
Climate Scenario ◽  
Amaranthus Retroflexus ◽  
Range Size ◽  
Weed Species ◽  
European Climate ◽  
Arable Weed ◽  
Temperate Europe ◽  
The Alps ◽  
Moderate Climate

We aimed at assessing establishment risk for 25 arable weed species in a changing European climate for the period 2051–2080. An increase (0.3–46.7%) in the range size was projected for the 14 species and a decrease (1.2–67.4%) for the 11 species in a future climate. The inclusion of the land use data increased the explanatory power of the models. The greatest increases in range sizes were projected for Amaranthus retroflexus, Papaver hybridum and Fumaria parviflora, and declines for Sinapis arvensis, Cerastium semidecandrum and Chenopodium rubrum. Application of a more severe climate scenario (HadCM3A2) affected decline (0.5–18.5%) for 12 species and increase (2.2–31.5%) for 13 species in the range size projections compared with the less severe (HadCM3B2) scenario. Both model scenarios projected high percentage species loss in Mediterranean and temperate Europe, but high species gain in the Alps, Carpathians and in boreal Europe. The results suggest that even under moderate climate scenarios drastic changes in the weed establishment risk can be expected to take place in Europe in the future.  

Comparison of weed communities in Manitoba ecoregions and crops

2000 ◽  
Vol 80 (4) ◽  
pp. 963-972 ◽  
Author(s):  
R. C. Van Acker ◽  
A. G. Thomas ◽  
J. Y. Leeson ◽  
S. Z. Knezevic ◽  
B. L. Frick
Keyword(s):  
Weed Management ◽  
Amaranthus Retroflexus ◽  
Weed Species ◽  
Canada Thistle ◽  
Wild Mustard ◽  
Polygonum Convolvulus ◽  
Weed Communities ◽  
Green Foxtail ◽  
Poaceae Family ◽  
Weed Survey

In 1997, a weed survey was conducted during July and August in fields of wheat, barley, oat, canola and flax in Manitoba. Field selection was based on a stratified-random sampling methodology using ecodistricts as strata. Species in the Poaceae family were most commonly observed in the survey, followed by species in the Polygonaceae, Asteraceae and Brassicaceae families. The six most abundant weed species were green foxtail [Setaria viridis (L.) Beauv.], wild oats (Avena fatua L.), wild buckwheat (Polygonum convolvulus L.), Canada thistle (Cirsium arvense L.), redroot pigweed (Amaranthus retroflexus L.) and wild mustard (Sinapis arvensis L.). The survey highlighted significant differences between ecoregions and between crops in residual weed infestations. The weed community in the Boreal Transition ecoregion was dominated by seven species, whereas fields in the Aspen Parkland and Lake Manitoba Plain ecoregions were dominated by two species and the Interlake Plain ecoregion was dominated by only one species. Although significant differences were found between the weed communities in crops, they were not as great as differences between ecoregions. The Manitoba residual weed community in 1997 was very similar to that reported for 1978–1981 and 1986, suggesting that the same species should remain a focus for weed management. Key words: Weed survey, weed relative abundance, weed distributions, Manitoba ecoregions

Response of Weeds to Soil pH

Weed Science ◽  
1975 ◽  
Vol 23 (6) ◽  
pp. 473-477 ◽  
Author(s):  
G. A. Buchanan ◽  
C. S. Hoveland ◽  
M. C. Harris
Keyword(s):  
Soil Ph ◽  
Sandy Loam ◽  
Plantago Lanceolata ◽  
Warm Season ◽  
Amaranthus Retroflexus ◽  
Low Ph ◽  
Sandy Loam Soil ◽  
Weed Species ◽  
Stellaria Media ◽  
Loam Soil

Ten warm-season and six cool-season weed species were grown in the glasshouse on Hartsells fine sandy loam soil and Lucedale sandy loam soil at pH levels from 4.7 to 6.3. Growth of species varied widely in response to soil pH as measured by herbage yield. Showy crotalaria (Crotalaria spectabilis Roth), coffee senna (Cassia occidentalis L.), and large crabgrass (Digitaria sanguinalis (L.) Scop.] were highly tolerant to low pH soils. Sicklepod (Cassia obtusifolia L.), annual bluegrass (Poa annua L.), Carolina geranium (Geranium carolinianum L.), and buckhorn plantain (Plantago lanceolata L.), were medium to high in tolerance. Jimsonweed (Datura stramonium L.), tall morningglory [Ipomoea purpurea (L.) Roth], crowfootgrass [Dactyloctenium aegyptium (L.) Richter], and prickly sida (Sida spinosa L.) were medium to low in tolerance to low soil pH. Growth of Florida beggarweed [Desmodium tortuosum (Sw.) DC], redroot pigweed (Amaranthus retroflexus L.), chickweed [Stellaria media (L.) Cyrillo], common dandelion (Taraxacum officinale (Weber), and wild mustard [Brassica kaber (DC.) L.C. Wheeler var. pinnatifida (Stokes) L.C. Wheeler] was severely reduced in soils with low pH.

Sign in / Sign up

Export Citation Format

Share Document